A spraycast method is described in U.S. Pat. No. 3,826,301 that involves atomizing a molten metal or alloy and directing the atomized spray onto a collector surface disposed in a spray chamber to form an article. The spray chamber typically is maintained at atmopsheric pressure of argon or other non-reactive gas therein while the molten spray is directed onto the collector.
U.S. Pat. No. 3,826,921, now Reissue 31,767, describes control of the temperature of the spray deposit independent of the temperature of a mold in which an atomized spray is directed to control the structure of the sprayed deposit. To this end, the patent focuses on the conditions of gas atomization of the molten metal or alloy in the atomizing chamber and not the conditions in the spray chamber.
The spraycasting method of making metallic articles continues to suffer from disadvantages that the sprayed deposit includes entrapped argon or other gas that increases porosity of the deposit, that cylindrical spray cast shapes exhibit fissure porosity proximate the inner diameter, and that yields of acceptable spraycast articles are unsatisfactorily low from a commercial production standpoint. Moreover, coarse grain banding is evident in the spraycasting of certain nickel base superalloys, such as IN718.